In the visualization of medical images it is a clinical standard procedure to select a certain “level” and “window” setting when, for instance, a tomographic medical image is to be viewed. This procedure is sometimes called the level-window technique. The aim is to enhance the contrast in a certain intensity range characteristic for a certain anatomical region and to use the gamut from, say, black to white to show the selected range. Since CT images have a well-defined scale (in Hounsfield units (HU)) it is very common to select a certain gray value window for a specific reviewing task, e.g. a dedicated lung window or bone window is defined. For other imaging modalities, such as MRI (magnetic resonance imaging), choosing the right visualization is more complicated since the scale is not as quantitative as in CT imaging. Therefore, MR images are very often normalized and gradient bias fields are suppressed, which is a technique necessary to allow window level settings to be useful beyond small, localized regions. Even without this, a similar level and window mapping as in CT is then used to (re)view MR datasets.
It has been observed by the Applicant that despite there being an abundance of predefined level-window settings dedicated to different anatomical contexts and tasks, some anatomical information may still slip the attention of the clinician during image (re)viewing.